Rechargeable battery, electrode assembly and method for manufacturing the same

ABSTRACT

A rechargeable battery, an electrode assembly, and an electrode assembly manufacturing method are disclosed. The electrode assembly includes: a separator configured to include a first insertion portion formed in a first direction and a second insertion portion formed in a second direction, which are alternatively stacked; a first electrode inserted into the first insertion portion; a second electrode inserted into the second insertion portion while the separator is disposed between the first electrode and the second electrode; a sealing portion configured to bond opposite surfaces of the separator into which the first electrode and the second electrode are inserted with the separator interposed therebetween; and a lead tab configured to include a first current collecting tab connected to the first electrode and a second current collecting tab connected to the second electrode.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional application of U.S. patent applicationSer. No. 16/345,206, filed Apr. 25, 2019, which is a National PhasePatent Application of International Patent Application NumberPCT/KR2017/013088, filed on Nov. 17, 2017, which claims priority ofKorean Patent Application No. 10-2016-0153900, filed Nov. 18, 2016. Theentire contents of all of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a rechargeable battery, an electrodeassembly, and a manufacturing method of the electrode assembly, whichhave no risk of short-circuiting and are improved in stability.

BACKGROUND ART

A rechargeable battery differs from a primary battery in that it can berepeatedly charged and discharged, while the latter is incapable ofbeing recharged. Low-capacity rechargeable batteries are used inportable electronic devices such as mobile phones, laptop computers andcamcorders, and large capacity batteries are widely used as powersources for driving a motor such as for hybrid vehicles.

The rechargeable battery includes a nickel cadmium (NiCd) battery, anickel hydrogen (NiMH) battery, a lithium (Li) battery, and a lithiumion (Li ion) rechargeable battery. In particular, the lithium ionrechargeable batteries are about three times higher in operating voltagethan the nickel cadmium batteries or nickel hydride batteries, which arewidely used as power sources for portable electronic equipment. Further,it is widely used because of its high energy density per unit weight.

The rechargeable battery mainly uses a lithium-based oxide as a positiveactive material and a carbonaceous material as a negative activematerial. The rechargeable batteries are classified into liquidelectrolyte batteries and polymer electrolyte batteries depending on atype of electrolyte, and a battery using a liquid electrolyte isreferred to as a lithium ion battery, while a battery using a polymerelectrolyte is referred to as a lithium polymer battery.

In the case where the electrode assembly is implemented as a stackedtype, the rechargeable battery may be deteriorated in stability due to ashort circuit caused by changes in positions where a positive electrodeand a negative electrode are stacked when a vibration is transferredthereto by external impact.

DISCLOSURE Technical Problem

An exemplary embodiment of the present invention has been made in aneffort to provide a rechargeable battery, an electrode assembly, and anelectrode assembly manufacturing method in which a short circuit due toan external impact does not occur.

Technical Solution

An exemplary embodiment of the present invention includes: a separatorconfigured to include a first insertion portion formed in a firstdirection and a second insertion portion formed in a second direction,which are alternatively stacked; a first electrode inserted into thefirst insertion portion; a second electrode inserted into the secondinsertion portion while the separator is disposed between the firstelectrode and the second electrode; a sealing portion configured to bondopposite surfaces of the separator into which the first electrode andthe second electrode are inserted with the separator interposedtherebetween; and a lead tab configured to include a first currentcollecting tab connected to the first electrode and a second currentcollecting tab connected to the second electrode.

The separator may be formed as a continuous zigzag type between thefirst electrode and the second electrode, the separator in which thefirst insertion portion and the second insertion portion arealternatively formed.

The sealing portion may bond opposite surfaces of the separator with thefirst electrode interposed therebetween at the first insertion portion.

The sealing portion may bond opposite surfaces of the separator with thesecond electrode interposed therebetween at the second insertionportion.

The sealing portion may bond edges of the separator in which the firstelectrode and the second electrode are stacked in plural.

The sealing portion may bond each edge of the separator of an uppermostside and a lowermost side on which the first electrode, the secondelectrode and the separator are stacked.

The sealing portions may bond the separator by using at least one ofthermal welding, ultrasonic wave welding, laser bonding, and anadhesive.

An exemplary embodiment of the present invention includes: a caseconfigured to accommodate the electrode assembly; a first electrode leadconnected to the first current collecting tab; and a second electrodelead connected to the second current collecting tab.

An exemplary embodiment of the present invention includes: (a) providinga separator between a first electrode and a second electrode in acontinuous zigzag type; and (b) sealing opposite side surfaces of theseparator with the first electrode or the second electrode of the step(a) interposed therebetween.

The step (b) may include sealing opposite side surfaces of the separatorwith the first electrode interposed therebetween by using a first sealerand a second sealer.

The step (b) may include sealing opposite side surfaces of the separatorwith the second electrode interposed therebetween by using a firstsealer and a second sealer.

The step (b) may include sealing each edge of the separator of anuppermost side and a lowermost side on which the first electrode, thesecond electrode and the separator are stacked.

In the step (b), the separator may be sealed by using at least one ofthermal welding, ultrasonic wave welding, laser bonding, and anadhesive.

According to the exemplary embodiment of the prevent invention, theseparator may be sealed at the upper side of the negative electrode orthe positive electrode in the process of stacking the negative electrodeand the positive electrode while interposing the separator therebetween,to prevent a positive change of the negative electrode or the positiveelectrode, thereby improving stability.

Advantageous Effects

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic perspective view of a rechargeablebattery according to an exemplary embodiment of the present invention.

FIG. 2 illustrates a schematic perspective view of the electrodeassembly of FIG. 1 .

FIG. 3 schematically illustrates main parts of a separator, a firstelectrode, and a second electrode which are disposed in a state where aportion of the electrode assembly of FIG. 2 is unfolded.

FIG. 4 illustrates a top plan view schematically showing that a sealingportion is formed at an upper portion and a lower portion of a negativeelectrode in a state where a portion of an electrode assembly accordingto a first exemplary embodiment of the present invention is unfolded.

FIG. 5 illustrates a side view schematically showing main parts of theelectrode assembly according to the first exemplary embodiment of thepresent invention in which the sealing portion is formed.

FIG. 6 illustrates a top plan view schematically showing that a sealingportion is formed at an upper portion and a lower portion of a positiveelectrode in a state where a portion of the electrode assembly accordingto a second exemplary embodiment of the present invention is unfolded.

FIG. 7 illustrates a side view schematically showing main parts of theelectrode assembly according to the second exemplary embodiment of thepresent invention in which the sealing portion is formed.

FIG. 8 illustrates a top plan view schematically showing that a sealingportion is formed in a state where a portion of the electrode assemblyaccording to a third exemplary embodiment of the present invention isunfolded.

FIG. 9 illustrates a side view schematically showing main parts of theelectrode assembly according to the third exemplary embodiment of thepresent invention in which the sealing portion is formed.

FIG. 10 illustrates a flowchart schematically showing an electrodeassembly manufacturing method according to the first exemplaryembodiment of the present invention.

FIG. 11 illustrates a side view schematically showing a state in which afirst sealer and a second sealer of FIG. 10 are installed.

FIG. 12 illustrates a flowchart schematically showing an electrodeassembly manufacturing method according to the second exemplaryembodiment of the present invention.

MODE FOR INVENTION

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention.

The drawings and description are to be regarded as illustrative innature and not restrictive. Like reference numerals designate likeelements throughout the specification.

Throughout this specification and the claims that follow, when it isdescribed that an element is “coupled/connected” to another element, theelement may be “directly coupled/connected” to the other element or“indirectly coupled/connected” to the other element through a thirdelement. In addition, unless explicitly described to the contrary, theword “comprise” and variations such as “comprises” or “comprising” willbe understood to imply the inclusion of stated elements but not theexclusion of any other elements.

Throughout this specification and the claims that follow, it will beunderstood that when an element such as a layer, film, region, orsubstrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. Further, in the specification, the word “˜on” or “˜over” meanspositioning on or below the object portion, and does not essentiallymean positioning on the upper side of the object portion based on agravity direction.

FIG. 1 illustrates a schematic perspective view of a rechargeablebattery according to an exemplary embodiment of the present invention,FIG. 2 illustrates a schematic perspective view of the electrodeassembly of FIG. 1 , and FIG. 3 schematically illustrates main parts ofa separator, a first electrode, and a second electrode which aredisposed in a state where a portion of the electrode assembly of FIG. 2is unfolded.

As illustrated in FIG. 1 to FIG. 3 , according to a first exemplaryembodiment of the present invention, a rechargeable battery 100 includesan electrode assembly 10 configured to including a separator 15, a firstelectrode 11, and a second electrode 13; a case 40 configured toaccommodate the electrode assembly 10 therein; lead tabs 21 and 23configured to include a first current collecting tab 21 connected withthe first electrode 11, and a second current collecting tab 23 connectedwith the second electrode 13; a first electrode lead 31 connected withthe first current collecting tab 21; and a second electrode lead 33connected with the second current collecting tab 23.

For example, in the electrode assembly 10, the first electrode(hereinafter referred to as a “negative electrode”) 11 and the secondelectrode (hereinafter referred to as a “positive electrode”) 13 may bedisposed on opposite surfaces of the separator 15, and the negativeelectrode 11, the separator 15, and the positive electrode 13 may befolded a predetermined number of times in a zigzag form.

In the present exemplary embodiment, the electrode assembly 10 may beformed to have a zigzag shape by stacking the negative electrode 11 andthe positive electrode 13 which are respectively inserted into spacesformed by folding the separator 15 the predetermined number of times.

In other words, the negative electrode 11 and the positive electrode 13,which are disposed at opposite sides of the separator 15, may berespectively inserted into first insertion portions 11 a and secondinsertion portions 13 a formed in the separator 15 that is bent in thezigzag shape.

The negative electrode 11 is disposed on one side of the separator 15,and the first current collecting tab 21 (hereinafter referred to as“negative electrode current collecting tab”) is connected to an uncoatedregion thereof. The negative electrode current collecting tab 21 isconnected to each negative electrode 13, and is installed to connect thenegative electrode 11 to the first electrode lead 31.

This negative electrode 11 may be disposed inside of the first insertionportions 11 a formed in the spaces between portions of the separator 15that are bent in the zigzag form. The negative electrode 11 may beformed by a stamping operation process by a press or the like, and aplurality of negative electrodes 11 may be disposed on a side surface ofthe separator 15.

The positive electrode 13 may be disposed on the other side of theseparator 15 at a position opposite to the negative electrode 11 withthe separator therebetween.

The positive electrode 13 may be disposed on the side surface of theseparator 15 in a rectangular shape by a punching operation process.Although the positive electrode is described to be formed to have arectangular shape in the present exemplary embodiment as an example, thepresent invention is not limited thereto, and the positive electrode 13may be formed in various shapes such as a round shape in a portionthereof.

The positive electrode 13 may be disposed inside of the second insertionportions 13 a formed in the spaces between portions of the separator 15that are bent in the zigzag form. The negative electrode 11 may beformed by a stamping operation process by a press or the like, and aplurality of negative electrodes 11 may be disposed on a side surface ofthe separator 15.

The positive electrode 13 may include a plurality of positive electrodes13, which are disposed on the side surface of the separator 15 in astate of being spaced apart from each other, and the second currentcollecting tab 23 may be connected thereto at each edge in a protrudingmanner.

As such, the negative electrode 11 and the positive electrode 13, whichare disposed at opposite sides of the separator 15, may be respectivelyinserted into the first insertion portions 11 a and the second insertionportions 13 a formed in the separator 15 that is bent in the zigzagshape.

The first inserting portion 11 a indicates a portion formed on one sidesurface of the separator 15 that is bent in the zigzag form, into whichthe negative electrode 11 is to be inserted. Similarly, the secondinsertion portion 13 a indicates a portion formed on the other surfaceof the separator 15 that is bent in the zigzag form, into which thepositive electrode 13 is to be inserted.

Meanwhile, the opposite surfaces of the separator 15 may be bonded toeach other by a sealing portion 20 in a process of inserting thenegative electrode 11 and the positive electrode 13 into the firstinsertion portion 11 a and the second insertion portion 13 a,respectively. This will be described in detail below.

FIG. 4 illustrates a top plan view schematically showing that a sealingportion is formed at an upper portion and a lower portion of a negativeelectrode in a state where a portion of an electrode assembly accordingto a first exemplary embodiment of the present invention is unfolded,and FIG. 5 illustrates a side view schematically showing main parts ofthe electrode assembly according to the first exemplary embodiment ofthe present invention in which the sealing portion is formed.

As illustrated in FIG. 4 and FIG. 5 , the negative electrode 11 may bestacked in a state where the negative electrode 11 is inserted into thezigzag bent surface of the first inserting portion 11 a. Herein, theopposite side surfaces of the separator 15 at an upper side and a lowerside of the negative electrode 11 with the negative electrode 11therebetween may be bonded to each other by the sealing portion 20.

The sealing portion 20 bonds the upper side and the lower side of thenegative electrode 11 at an open side of the first insertion portion 11a in the separator 15, and thus the negative electrode 11 may berestrained in a state in which a position thereof is fixed inside of thefirst insertion portion 11 a.

Accordingly, the negative electrode 11 is stably positioned in the firstinserting portion 11 a by the sealing portion 20 even when vibration isgenerated by an impact from the outside of the rechargeable battery 100,and thus it is possible to effectively prevent a short circuit caused bya change in a position of the negative electrode 11.

The sealing portion 20 is exemplarily illustrated as being bonded to theopposite side surfaces of the separator 15 by thermal welding in thepresent exemplary embodiment.

However, the bonding of the sealing portion 20 is not necessarilylimited to thermal welding, and may be applied to any one of ultrasonicwave welding, laser bonding, and an adhesive.

As described above, in the electrode assembly 10 of the secondarybattery 100 of the present exemplary embodiment, the negative electrode11 and the positive electrode 13 are stacked with the separator 15interposed therebetween, while the separator 15 is provided in a zigzagstaggered manner.

Herein, since the opposite surfaces of the separators 15 with thenegative electrode 11 or the positive electrode 13 therebetween arebonded to each other, the negative electrodes 11 and the positiveelectrodes may be stably positioned. Therefore, the negative electrode11 and positive electrode 13 may be prevented from being shifted tosuppress a short circuit, thereby improving stability of therechargeable battery 100.

FIG. 6 illustrates a top plan view schematically showing that a sealingportion is formed at an upper portion and a lower portion of a positiveelectrode in a state where a portion of the electrode assembly accordingto a second exemplary embodiment of the present invention is unfolded,and FIG. 7 illustrates a side view schematically showing main parts ofthe electrode assembly according to the second exemplary embodiment ofthe present invention in which the sealing portion is formed. The samereference numerals as those of FIG. 1 to FIG. 5 denote the same orsimilar members having the same or similar functions. Hereinafter,detailed descriptions of the same reference numerals will be omitted.

As illustrated in FIG. 6 and FIG. 7 , according to the second exemplaryembodiment of the prevent invention, a sealing portion 120 of anelectrode assembly 110 seals an upper portion and a lower portion of thepositive electrode 13 inserted into the second insertion portion 13 a onthe zigzag-bent surface of the separator 15.

Accordingly, the positive electrode 13 is stably positioned in thesecond insertion portion 13 a by the sealing portion 120 even whenvibration is generated by an impact from the outside of the rechargeablebattery 100, and thus it is possible to effectively prevent a shortcircuit caused by a change in a position of the positive electrode 13.

FIG. 8 illustrates a top plan view schematically showing that a sealingportion is formed in a state where a portion of the electrode assemblyaccording to a third exemplary embodiment of the present invention isunfolded, and FIG. 9 illustrates a side view schematically showing mainparts of the electrode assembly according to the third exemplaryembodiment of the present invention in which the sealing portion isformed. The same reference numerals as those of FIG. 1 to FIG. 7 denotethe same or similar members having the same or similar functions.Hereinafter, detailed descriptions of the same reference numerals willbe omitted.

As illustrated in FIG. 8 and FIG. 9 , according to the third exemplaryembodiment of the present invention, in a sealing portion 220 of anelectrode assembly 210 an upper edge portion and a lower edge portion ofthe zigzag-bent separator 15 are bonded in a state where the negativeelectrode 11 and the positive electrode 13 are respectively disposedinside of the first insertion portion 11 a and the second insertionportion 13 a.

As a result, according to the present exemplary embodiment, theelectrode assembly 210 may effectively prevent a short circuit caused bychanges in positions where the negative electrode 11 and the positiveelectrode 13 are stacked when a vibration is transferred thereto byexternal impact, by connecting the upper edge portion and the lower edgeportion of the separator 15 in a state where the separator 15, thenegative electrode 11, the positive electrode 13 are stacked as unitbodies.

FIG. 10 illustrates a flowchart schematically showing an electrodeassembly manufacturing method according to the first exemplaryembodiment of the present invention, and FIG. 11 illustrates a side viewschematically showing a state in which a first sealer and a secondsealer of FIG. 10 are installed. The same reference numerals as those ofFIG. 1 to FIG. 9 denote the same or similar members having the same orsimilar functions. Hereinafter, detailed descriptions of the samereference numerals will be omitted. Hereinafter, a rechargeable batterymanufacturing method will be described in detail below.

First, the first electrode 11 and the second electrode 13 are providedwith the separator 15 interposed therebetween (S10). Hereinafter, thefirst electrode 11 serves as a negative electrode, and the secondelectrode 13 serves as a positive electrode.

The separator 15 in step S10 may be provided in a continuous zigzagfashion between the first electrode 11 and the second electrode 13.

Herein, the first electrode 11 may be provided to the first insertingportion 11 a formed on one side of the zigzag bent portion of theseparator 15, and the second electrode 13 may be provided to the secondinsertion portion 13 a formed on the other side of the zigzag bentportion of the separator 15.

Next, side surfaces of the separator 15 are sealed at an edge portion ofthe separator 15 with the first electrode 11 or the second electrode 13interposed therebetween. For this purpose, a first sealer 111 and asecond sealer 113 may be provided with the first electrode 11 or thesecond electrode 13 interposed therebetween, to bond the separator 15with the upper and lower portions of the first electrode 11 or thesecond electrode 13.

In step S20, the side surfaces of the separator 15 may be sealed at theupper portion and the lower portion of the first electrode 11 or thesecond electrode 13 in a state where the first electrode 11 and thesecond electrode 13 are respectively disposed inside of the firstelectrode 11 and the positive electrode 13 formed on one side and theother side of the separator 15 bent in a zigzag shape.

In the present exemplary embodiment, step S20 is exemplarily illustratedas sealing the separator 15 at the upper portion and the lower portionof the first electrode 11 by the sealing portion 20 formed by using thefirst sealer 111 and the second sealer 113. However, the sealing portion20 is not necessarily limited to sealing the upper portion and the lowerportion of the first electrode 11, and the upper portion and the lowerportion of the second electrode 13 may be sealed by using the firstsealer 111 and the second sealer 113.

Herein, in step S20, the sealing of the separator 15 may be performed byusing thermal welding, ultrasonic wave welding, laser bonding, or anadhesive.

FIG. 12 illustrates a flowchart schematically showing an electrodeassembly manufacturing method according to the second exemplaryembodiment of the present invention. The same reference numerals asthose of FIG. 1 to FIG. 11 denote the same or similar members having thesame or similar functions. Hereinafter, detailed descriptions of thesame reference numerals will be omitted. Hereinafter, a rechargeablebattery manufacturing method will be described in detail below.

First, the first electrode 11 and the second electrode 13 are providedwith the separator 15 interposed therebetween (S110). The separator 15in step S110 may be provided in a continuous zigzag fashion between thefirst electrode 11 and the second electrode 13.

Next, an uppermost edge portion and the lowermost edge portion of theseparator 15 that is bent in the zigzag shape are sealed with each otherin the electrode assembly 10 in which the first electrode 11 and thesecond electrode 13 are stacked as a unit body with the separator 15interposed therebetween (S120).

That is, the sealing may be performed in a state where the firstelectrode 11 and the second electrode 13 are disposed inside of theseparator 15, by respectively disposing the first sealer 111 and thesecond sealer 113 at an uppermost end and a lowermost side of theelectrode assembly 10.

As such, since the sealing is performed between the uppermost end andthe lowermost end of the separator 15 in a state where electrodeassemblies 10 are stacked as a unit body, the first electrode 11 and thesecond electrode 13 may be stably stacked so as to prevent short circuitoccurrence.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

DESCRIPTION OF SYMBOLS

-   -   10 . . . electrode assembly    -   11 . . . negative electrode    -   11 a . . . first insertion portion    -   13 . . . positive electrode    -   13 a . . . second insertion portion    -   15 . . . separator    -   20 . . . sealing portion    -   21 . . . first current collecting tab    -   23 . . . second current collecting tab    -   31 . . . first electrode Lead    -   33 . . . second electrode lead    -   111 . . . first sealer    -   113 . . . second sealer

1. An electrode assembly manufacturing method comprising: (a) providinga separator between a first electrode and a second electrode in acontinuous zigzag type; and (b) sealing opposite side surfaces of theseparator with the first electrode or the second electrode of the step(a) interposed therebetween.
 2. The electrode assembly manufacturingmethod of claim 1, wherein the step (b) includes sealing opposite sidesurfaces of the separator with the first electrode interposedtherebetween by using a first sealer and a second sealer.
 3. Theelectrode assembly manufacturing method of claim 1, wherein the step (b)includes sealing opposite side surfaces of the separator with the secondelectrode interposed therebetween by using a first sealer and a secondsealer.
 4. The electrode assembly manufacturing method of claim 1,wherein in the step (b), the step (b) includes sealing each edge of theseparator of an uppermost side and a lowermost side on which the firstelectrode, the second electrode and the separator are stacked.
 5. Theelectrode assembly manufacturing method of claim 1, wherein in the step(b), the separator is sealed by using at least one of thermal welding,ultrasonic wave welding, laser bonding, and an adhesive.